Turn a Musical Greeting Card Into an Alarm Clock?


My sister in law just gave my son a musical greeting card for his birthday. It has a catchy (i.e., annoying) song – in Dutch no less, flashing lights and an element that spins around. It occurs to me that it would make a fantastic alarm clock as it is the most annoying thing on the planet.

Anyone know of any good hack instructions on how to take the electronics from the card and hook it up to some kind of clock kit? Or anything else for that matter. The ultimate plan is to re-gift it back to said sister-in-law (assuming of course I can pry it out of my son’s hands).

I figure that it is possible but electronics is not my strong suit so any and all suggestions would be appreciated.

The trigger for the card will be either a small microswitch or a optical sensor of some sort - the last one I had used a microswitch. You would need to remove the microswitch and replace it with a relay controlled by the alarm. You will need a specialist digital or electric clock movement to do this, although a hobby shop supporting clock makers may have an appropriate movement. Digital clock modules also often supply relay control lines, but you need to be an electronic enthusiast to attempt using that.

I would go for doable but tricky

Why do you not find an alarm clock that lets you record your own alarm sound?

Then you can record the annoying song and smash the record button before sending it off :wink:


PS I was given a birthday card with “You’re the one that I want”. I extracted the module, and hid it in the seat back of someone from work. Unfortunately I had left before they got back - but it was funny whenever someone borrowed the chair.

What sets the annoyingness off? Maybe there is a way to do this mechanically instead of electronically.

Analog wind-up alarm clocks have a key on the back that spins wildly when the alarm sounds, perhaps there is some way for you to translate the movement of that spinning key to the mechanism that activates the card?

If you post what you understand of the lyrics, I can get the spelling right for you so you can search for a right wav or mp3 file of that song.

An old fashioned mechanical alarm clock has a key on the back that spins when the alarm goes off. You can have this wind up a string that would pull a weight off the microswitch that keeps the card off.

This video may help you:
Great Keyboard Practical Joke!
It’s about hooking up a greeting card to a computer keyboard, but the technique should also be applicable to an alarm clock.